I whack in heavy but very useful (in my opinion) tools, for example shovels, fireaxes, etc. Having two shopping carts near your base is good, because you can use another for gallon jugs of liquids you’re going to need like gasoline and water. (Gallon jugs are pretty hard to carry by yourself.) Also shopping carts act as a portable bush for killing zombies with your melee weapons; walking through one costs 400 move points.
Either that or just whack it full of mininukes and see that stupid ‘looks like you need an ID card for that’ message pop up at you now.
BOMBS AWAY!!!